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Selecting the right building material is crucial for any construction. Although the contractor may be arranging the material, yet it is advisable for you as the house owner to be aware of methods to ascertain the quality of the material being used. This is especially important if you are not using ready-mix concrete.
SAND :
In technical language, sand is referred to as Fine Aggregates. Size of particles is less than 5 mm. River sand is cheapest source of natural aggregates. It should be free from dust, clay, silt and organic impurities.
You can conduct a simple field test for sand:
Hold some of the sand in hand, rub it and just throw it. Check your palm. Good sand will not stick to the palm.
Take some sand in a graduated, transparent measuring cylinder and pour double the quantity of water to it. Shake it vigorously for two minutes by keeping the palm on the top of the cylinder. Keep the cylinder for one hour in undisturbed condition. Different layers will be observed enabling you to check the quality of the sand.
COARSE AGGREGATES :
Crushed hard stone and gravel are common materials used as coarse aggregates for concrete work in India. Aggregates are available in sizes of 40mm, 20mm and 10mm. For residential slab, beam and column work, 20mm and 10mm size of aggregates are generally used
Aggregates should be hard, strong and durable. They must also be free of clay, loam, vegetable and other foreign materials. As far as possible, flaky and elongated pieces of stone should be avoided.
WATER :
Municipal water supplied for drinking purpose is generally considered fit for construction purpose. Additionally, you can check if the water is free of oil, acids, salts and organic impurities. Sea-water and ground water should preferably not be used for construction purposes.
BRICKS :
Bricks should be sound, hard and well burnt.
They should be free from effloresces and be uniform in size, shape and colour.
The bricks when struck together should produce a good metallic ringing sound.
They must not break when dropped from a height of approximately a meter.
Construction Tips :
In case of any construction project, proper planning is very important to ensure that the timelines are met and the construction is strong and durable. With the rapid development taking place in the industry, there is often a multiplicity of factors to be considered and decision making can be complex. To avoid your dependency upon the site engineer or contractor, it is advisable to be aware of certain important aspects with regard to construction planning.
Building Configuration :
An important feature is regularity and symmetry in the overall shape of the building. A building shaped like a box, such as rectangular both in plan and elevation is inherently stronger than one that is L-shaped or U-shaped such as a building with wings.
Separation of Blocks :
Separation of a large building into several blocks may have to be done in order to obtain symmetry and regularity of each block. Separated sections can be treated just like expansion joints.
Adverse Elements :
Even before the construction commences, it is essential to check for certain adverse factors whose existence would necessitate the abandonment of that particular site for construction.
1. Immediate neighbourhood of rivers carrying heavy floods
2. Reclaimed soils; land subject to subsidence or settlement
3. Smoke or obnoxious odour due to vicinity to industrial areas
Besides the above factors, you must also ensure that the construction site should not be a part of a land depression. The topographical conditions of a site not only determine its elevation and foundation, but also affect the laying of sewers and drains.
Geological Conditions :
The geological conditions of the site are also important factors to be considered due to their effect on the foundation and the subsequent life and strength of the construction. If there is a rocky base on the surface or below, the site is optimum as it provides an excellent base for laying the foundation and also prevents damage due to moisture.
Orientation :
In northern India, longer walls are generally placed towards north & south and shorter walls towards east & west, so that minimum possible walls are exposed to the sun. The general wind direction of the site also determines the orientation of the building.
Plinth :
It is a good practice to keep plinth level 60 to 75 centimetres above natural ground level.
Damp Proof Course
Provide a Damp Proof Course (D.P.C.) at plinth level in cement concrete by adding water -proofing compound in the ratio 1 : 2 : 4.
R.C.C. Bands
Provide R.C.C. bands at sill, lintel and roof levels for load bearing constructions.
Brick Masonry
Soak the red bricks in clear water thoroughly before use.
It is desirable to provide expansion joints after every 30 meter length of wall.
Half brick masonry wall should be reinforced with suitable reinforcement at every third or fourth course of wall.
Selecting the right building material is crucial for any construction. Although the contractor may be arranging the material, yet it is advisable for you as the house owner to be aware of methods to ascertain the quality of the material being used. This is especially important if you are not using ready-mix concrete.
Using the right proportions of raw material is essential for obtaining an optimum quality of concrete mix. Although it is advisable to seek professional advice for determining the proportions, this chart can be used as a ready reference:
Use/Application Proportion on volumetric basis
Cement Sand Stone Aggregates
Plain Cement Concrete (PCC) 1 3 6
RCC footing column, beam, slab, etc. 1 1.5 3
Brick Masonry (23 cm and above) 1 6 -
Brick Masonry (Less than 23 cm) 1 3 -
Cement plaster on wall 1 4 -
Cement plaster on ceiling 1 3 -
Ceramic tiles fixing 1 4 -
IPS flooring 1 2 4
Cement concrete for
Footpath /Internal roads in housing societies 1 1.5 3
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